A friend had made it for the "Gift of Life" fundraiser for Hern before he leaves for Mayo Clinic in Rochester, Minn., Thursday for kidney transplant surgery.

Hern, a 33-year-old St. Petersburg resident, surprised friends and family members a few weeks ago when he announced that he was considering donating his kidney to a stranger in need.

Thursday one of his kidneys will go to Cassey Sanger, a 28-year-old from Panora, Iowa.

Hern calls it a shotgun kidney donation because of how fast it all happened. Typically, the wait time between when a donor is found and the transplant surgery is three to four months. But Sanger, who suffers from kidney failure and has been on dialysis for the past six years, needed a new kidney as soon as possible.

She'd had a failed kidney transplant in the past. Since then more than 60 people have tried donating to her, but her blood and her antibodies were a barrier to all potential donors. Except Hern.

Two weeks to the day after doctors told them they were a match, Hern and Sanger will undergo extensive blood testing and a six-hour surgery. Both will be in the hospital for a few days then spend six to eight weeks on bed rest recovering.

Hern, an independent construction contractor, will be unable to work during that time.

He is unfazed and self-effacing as he talks about the surgery. His green eyes are downcast, and he is careful with his words, not wanting to sound proud.

Hern was inspired to sign up with Matching Donors, a nonprofit live donor services organization, when a friend on dialysis had a successful kidney transplant. He had watched his friend endure years of thrice-weekly dialysis treatments and thought that no one should have to go through life hooked to a machine.

"She'll be able to do anything she wants," Hern said of Sanger. "She'll be able to go on vacation, she'll be able to go on walks. Hopefully that'll all change for her."

More than 300 people came to Saturday's fundraiser, which was thrown together at the last minute by Hideaway Café owner John Kelly, a longtime friend of Hern's. Many attending participated in a silent auction and raffle of items donated by St. Petersburg businesses; others were passers-by who stopped in to donate.

"For everyone here, it doesn't surprise them what Christian is doing," his mother, Beth Hern, said at the fundraiser. "He's giving a part of himself, but that's just Christian. Whether it's his kidney or something else, he's always been empathetic to other people."

The event raised more than $6,600 for Hern, who was adamant that anything he doesn't need will go toward Sanger's medical bills.

Sanger was unable to comment this week. She is undergoing intensive treatments to remove harmful antibodies from her blood and weaken her immune system so that her body will not reject Hern's kidney. Last week she wrote a letter to Beth Hern, thanking her for raising Hern the way she did.

"As a mother you know how special the gift of life is," Sanger wrote.

"To date I have spent about 4,680 hours attached to a machine that can only prolong my life. I have had 19 different operations and countless days of not feeling well enough to sit up in bed.

"Christian is giving me that chance. … Thank you for raising such an amazing man. Your son is saving my life."